Flexible foams, such as for example, flexible urethane foams, are employed for a variety of purposes and may, for example, be molded into cushions, seats and other uses, particularly for the automotive and other industries. The flexible urethane foams for use in the automotive industry are typically prepared by a standard reaction of a polyol(s) with an isocyanate(s) in the presence of a catalyst or catalysts and also a blowing agent(s), such as water, with or without a halocarbon, to provide a foam reaction mixture which results in a mixture of both open and closed cells. In one application in the automotive industry flexible urethane foams are cold cured flexible foams to form high resilience molded polyurethane foam parts. In the auto and other industries the foam formulations employed are such that it is necessary to crush or open up the resulting molded foam prepared immediately or shortly after preparation because the foam product prepared tends to shrink and lose dimensional stability.
For example, in the automotive industry, the flexible cold cured urethane foams are prepared and introduced into a mold to form various foam products. The resulting molded foam product must be treated by cell opening techniques in order to provide a suitable product of desired dimensional stability. Normally within 15 to 90 seconds after demolding the foam product is passed through a pair(s) of nip rollers to crush the foam, or the foam is put in a vacuum to cause a similar action, or air injection may be introduced into the foam product, all with the purpose of providing a cell opening effect. A discussion of the problems of molded foam and one suggested cell opening technique is described in a Union Carbide Corporation bulletin "Novel Cell Opening Technology for HR Molded Foam," K. D. Cavender, 1985, incorporated by reference herein.
If such cell opening techniques are not employed with such foams, then the foams after demolding start to shrink and become wrinkled. The lack of dimensional stability of the resulting foam product is generally accepted as arising from an excessive amount of closed cells in the foam product with gases trapped in closed cells, which gases are hot during the expansion cycle, and which after demolding and cooling of the foam product contract, resulting in a loss of dimensional stability to the foam product. The process and mechanical techniques now employed in the industry to impart dimensional stability are designed to crush and thereby open the cells in order to impart dimensional stability to the foam product.
It is therefore desirable to provide a new technique and means to impart dimensional stability to flexible foam products whereas to either eliminate the present technique to crush or open up the foam product or to provide a foam product with a low or minimal need for the employment of other techniques for the crushing or opening up of the foam product.